In brake apparatuses for hydraulic motor vehicle brake systems, conventional brake devices with negative-pressure brake force boosters, hydraulic tandem master brake cylinders and a downstream, electronically closed-loop-controlled modulator unit for closed-loop driving dynamics control functions are still regarded as being particularly lightweight, inexpensive, easy to produce and as exhibiting the most comfortable pedal feel and response characteristics. With ever-increasing demands on automated, computer-controlled driving and braking, and at the same time an ever-decreasing available structural space, negative-pressure brake force boosters, which are of large construction, reach their technical limits.
Use is therefore made of brake devices with more compact hydraulic booster stages. Known brake devices with hydraulic booster stages are however normally of highly complex construction, are reliant on heavy and expensive high-pressure accumulators as a pressure source, often require special, separate fastening interfaces that are incompatible with conventional systems, and furthermore have potential for improvement with regard to their response characteristic.